/Engine/Source/Developer/DirectoryWatcher/Public/DirectoryWatcherModule.h
Register external changes that the OS file watcher couldn't detect (eg, a file changing in a UE sandbox)
virtual void RegisterExternalChanges ( [TArrayView](API\Runtime\Core\Containers\TArrayView)< const [FFileChangeData](API\Developer\DirectoryWatcher\FFileChangeData) > FileChanges ) const